1. Field of the Invention
This invention is directed to a control device for a vehicle, which controls the behavior of the vehicle based on information regarding the route that the vehicle follows. This information is output by a route information detector.
2. Related Art
Generally a vehicle has a behavior control system, for example, an engine or a transmission. Control patterns applied to the behavior control system are either manually selected by the driver or automatically based on selected driving conditions detected by various sensors. But, both ways of selecting the control patterns are executed after encountering an actual vehicle condition change, hence behavior controls of the vehicle are delayed relative to actual road conditions, so it is possible to make the drivability of the vehicle worse.
Recently, it has become possible for a route information detection system, for example, a navigation system, to detect in advance information regarding the road conditions on which the vehicle travels, and this information is used to control the control patterns which are applied to the engine and automatic transmission in order to control the behavior of the vehicle as desired. An example of a vehicle control system is disclosed in Japanese Laid Open Publication No. HEI 8-72591.
In the above mentioned application, the vehicle control system for a vehicle has a location detection means, which detects the present location of the vehicle, a operating road predicting means, which predicts the future location of the vehicle in a few seconds later by referring to an electronic map, a running resistance measuring means, which measures the present load condition of driving systems of the vehicle, a driving force predicting means, which predicts the driving force at the predicted future location of the vehicle by correcting the present load condition on the basis of slope information from the electronic map, a driving system control unit, which controls in advance either the engine or the automatic transmission in order to get sufficient driving force of the predicted driving force to correspond and furthermore to reduce fuel consumption as much as possible, and a running locus recording means, which detects the information on the vehicle speed, and records and accumulates this information in the electronic map.
According to the above mentioned control system, by controlling the engine or the automatic transmission to get a predicted driving force, which corresponds to the condition of future location of the vehicle, and which is determined by the driving force predicting means, the vehicle is able to maintain the appropriate driving force for the road condition. Furthermore, it improves the drivability on an actual road condition by reflecting the driver's intention to the control of the driving force.
In the above mentioned control system of the vehicle, because the route information is detected on the basis of radio waves from man-made satellites and the signals from various sensors, if the vehicle operates in places where the radio waves barely reach or the sensors fail, it is possible not to detect the correct route. As a result, the problem arises that the driving force of the vehicle is inappropriate to the road condition and the drivability deteriorates.
One of the examples, which deals with this problem, is an invention disclosed in Japanese Patent Laid Open Publication No. 5-262251. A control system for a vehicle has a running information output means, which outputs the information about the location of the vehicle, a moving condition control means, which controls the condition of the vehicle on the basis of the output of the running information, and a control rule changing means, which changes the rule on the basis of whether the running information output means is normal or not. So, even if the running information output means has failed, the control for the vehicle controls the vehicle without deteriorating the accuracy of the driving performance.
Although, it is possible that the outputted information includes an error within a certain degree, even if the running information output means, which outputs the information, is operating normally. Under this circumstance, if the predetermined moving condition control, which is appropriate to the fail condition of the information output means, is executed, the moving condition of the vehicle does not adapt to the road condition. As a result, it is possible that the drivability deteriorates.
But in the control system for the vehicle, disclosed in the HEI 5-262251, the control rules for the moving condition control means are automatically changed on the basis of whether the information, which is normal or fail. So, if the information output means deteriorates and consequently, the accuracy of the information is bad, and as the moving condition control is executed based on either the normal rule or the failure rule, it is difficult to meet the actual situation.